1. Field of the Invention
The present invention relates to a power transmission apparatus of a clothes washing machine adapted to transmit power during washing and spin-drying processes.
2. Description of a Prior Art
Typically, a washing machine is provided with a washing tub 3 in a body 1 as illustrated in FIG. 1.
The washing tub 3 is provided at a bottom surface thereof with power transmission means 13 for receiving a turning effect of a motor 5 through a belt 7 to thereby drive a spin-drying tub 9 or a pulsator 11.
In other words, the washing tub 3 is provided at an interior thereof with a spin-drying tub 9 for spin-drying laundry according to a centrifugal force generated by a driving of the motor in such way as to be rotated on a driving axis of the power transmission means 13.
The pulsator 11 disposed on the driving axis of the power transmission means 13 is provided at an interior of the spin-drying tub 9 in order to oscillate according to the driving of the motor 5 to thereby agitate washing water stored in the spin-drying tub 9 and to carry out the washing.
The body 1 is constructed at an upper side thereof with water supply means 14 for being connected to a faucet 12 to thereby supply the washing water into the washing tub 3, and the washing tub 3 includes at a lower surface thereof drainage means for draining the washing water.
In the conventional washing machine thus constructed, when the laundry is put into the spin-drying tub 9 in the washing tub 3 and a washing condition is selected on a control panel (not shown), the washing water (by way of example, warm water or cold water) is supplied to the spin-drying tub 9 through the water supply means 14 according to an opening operation of the faucet 12, and then the turning effect according to activation of the motor 5 is reduced through the power transmission means 13, to thereby be transmitted for rotation of the pulsator 11.
At this time, the pulsator keeps oscillating, to thereby cause the water in the spin-drying tub 9 to be in turbulence, and at the same time, to carry out the washing by adding a physical force to the laundry.
When the washing process is completed, the washing water is discharged according to activation of drainage means 15, and at the same time, water is supplied again through the water supply means 14. A rinsing process is carried out several times and then the spin-drying tub 9 performs a drying job on the laundry according to the centrifugal force generated by the spin-drying tub 9 rotating at a high speed, to thereby complete the washing.
Meanwhile, a power transmission apparatus, as illustrated in FIG. 2, has a rotatable driving washing shaft 19 fixedly mounted to a pulley 17 for being rotated by a belt 7 according to a driving of the motor 5, and the driving washing shaft 19 is provided at an exterior lower side thereof with a driving coupling 21 and at the same time, a first spin-drying shaft 23 is rotatably supported at an upper side thereof by a bearing 33. The first spin-drying shaft 23 is coupled at an upper side thereof to a connector 25 functioning as a brake drum, thereby rotating integrally with the first spin-drying shaft 23.
The connector 25 is connected at an upper side thereof to a second spin-drying shaft 27, which is thereby rotating integrally with the connector, and the second spin-drying shaft 27 is coupled at an upper side thereof to the spin-drying tub 9, so that the tub 9 can rotate with the connector 25.
The interior of the second spin-drying shaft 27 is provided with a washing shaft 29 mounted at an upper end thereof to the pulsator 11 through the intermediary of a bushing member (not shown).
In the meantime, rotation from the driving washing shaft 19 to the shaft 29 is reduced in speed by a planetary gear (not shown) within the connector 25.
Furthermore, the first spin-drying shaft 23 is supported by the lower bearing 33 inserted into a lower case 31, so that the first spin-drying shaft 23 can easily rotate, and the second spin-drying shaft 27 is supported by an upper bearing 37 inserted into an upper case 35, so that the second spin-drying shaft 27 can easily rotate.
The connector 25 is provided at a periphery thereof with a brake band 39 so that racing of the spin-drying tub 9 can be prevented during the washing process and at the same time, the band can perform a braking function against the spin-drying tub 9 during stoppage of the spin-drying process. The brake band 39 is supportedly connected to a brake lever 41.
A clutch spring 45 supported by a clutch boss 43 is arranged over the first spin-drying shaft 23 and the driving coupling 21, and the clutch boss 43 is connected to a clutch lever 49 by a connecting member 47.
In the power transmission apparatus thus constructed, the brake lever 41 is activated to cause the brake band 39 to be in a wound (braking) state during the washing process, and the clutch lever 49 is activated to cause the clutch spring 45 to be in an unwound (non braking) state.
The driving washing shaft 19 and the first spin-drying shaft 23 are thus in a relatively rotatable state.
The turning effect generated by the motor 5 and transmitted from the driving washing shaft 19 to the washing shaft 29 is reduced in speed by a planetary gear in the connector 25.
The pulsator 11 coupled to an upper side of the longitudinally washing shaft 29 oscillates repeatedly to carry out the washing.
At this time, the spin-drying tub 9 tends to be rotated by the laundry and the water current, however that tendency thereof can be prevented by the brake band 39.
During the spin-drying process, the states of the brake lever 41 and the clutch lever 49 are reversed from that of the washing process, thereby unwinding the brake band 39, and at the same time, winding the clutch spring 45, so that the driving washing shaft 19 and the first spin-drying shaft 23 are locked for common rotation.
Accordingly, the turning effect of the motor 5 is transmitted from the driving washing shaft 19 through the first spin-drying shaft 23, connector 25, and the second spin-drying shaft 27 in that order, so that the spin-drying tub 9 fixed to an upper side of the second spin-drying shaft 27 is rotated to thereby perform the spin-drying.
During the stoppage of the spin-drying process or during an electrical black-out, the brake lever 41 is activated, thereby causing the brake band 39 to be in a unwound state and to cease the rotation of the spin-drying tub 9.
However, according to the conventional power transmission apparatus thus constructed, there is a problem in that the clutch spring used for transmission of the power, requires the provision of a number of components whereby a manufacturing cost thereof has increased and the clutch spring has failed to completely transmit the electric power.
As a prior art another conventional power transmission apparatus in a washing machine, is disclosed in Japanese Utility model publication No. Hei 2-46861.
The power transmission apparatus disclosed in the publication No. Hei 2-46861, as illustrated in FIG. 3, comprises a washing shaft 19' mounted to a pulsator 11' and a spin-drying shaft 23' mounted to a spin-drying tub 9'. During a washing process, only the washing shaft 19' is driven (i.e., oscitted), and during a spin-drying process, the spin-drying shaft 23' along with the washing shaft 19' is rotated by a clutch spring 45'. The power transmission apparatus disclosed in the publication No. Hei 2-46861 is characterized by a one-way clutch for transmitting the power in such way that the spin-drying shaft 23' is rotated in a spin-drying direction only, and is prevented from rotating in a reverse direction.
In the power transmission apparatus thus constructed, the washing is carried out during the washing process by the oscittation of the pulsator 11' only according to the oscittation of a motor (not shown), and during the spin-drying process, the spin-drying is performed by simulataneous rotations of the pulsator 11' and the spin-drying tub 9'.
However, there is another problem in that an overload may occur in the motor 5' because of a construction of the clutch spring 45', whereby a life span of the motor 5' is shortened. Also, due to the clutch spring 45' and numerous components related thereto, difficulty in processing the components, manufacturing costs are increased and a complete transmission of the power cannot be accomplished.
Accordingly, the present invention is intended to solve the aforementioned problems, and it is an object of the present invention to provide a power transmission apparatus of a washing machine employing an electromagnet for transferring an electric power, thereby reducing a manufacturing cost and at the same time, carrying out a complete transmission of the power during washing and spin-drying processes.